| Soknedal Eiendom AS | Real estate | 2008 |
| Sol Investments AS | | 2021 |
| Solbakken Sjøside AS | Real estate | 2023 |
| Solbakken Velforening Ba | Other services | 1994 |
| Solberg Maskin AS | Construction | 2012 |
| Soldalen AS | Professional & scientific | 2004 |
| Soldi HR AS | Professional & scientific | 2022 |
| Soldi Regnskap AS | Professional & scientific | 1988 |
| Solem Invest Norge AS | | 2026 |
| Solemsli Holding AS | | 2024 |
| Solfrid Aune AS | Transport & logistics | 2019 |
| Solgruppen AS | Administrative & support | 1994 |
| Solid Stage Crew AS | Administrative & support | 2025 |
| Solid Trondheim AS | | 2025 |
| Solkysten Eiendom AS | Real estate | 2013 |
| Solli Arkitektkontor AS | Professional & scientific | 2021 |
| Sollihaug Holding AS | Financial services | 2016 |
| Solmar Invest AS | Financial services | 2013 |
| Solsiden AS | Real estate | 1989 |
| Solsiden Bilvask AS | Other services | 2010 |
| Solsiden Brygge AS | Real estate | 2012 |
| Solsiden Golf AS | Real estate | 2013 |
| Solsiden Investor AS | | 2026 |
| Solsiden Legesenter AS | Health & social care | 2024 |
| Solsiden Spa Og Velværesenter AS | Other services | 2003 |
| Solsjø AS | | 2021 |
| Solstad Utvikling AS | Real estate | 2018 |
| Solstaden Eiendomsutvikling AS | Real estate | 2023 |
| Solstorm Founders Fund AS | | 2020 |
| Solstorm Rocket Propulsion AS | Professional & scientific | 2020 |
| Solvangen Barnehage SA | Education | 2000 |
| Solve International AS | Professional & scientific | 2024 |
| Soløy Holding AS | | 2019 |
| Somaveien 10 AS | Real estate | 2008 |
| Some Garden AS | Information & communication | 2024 |
| Sommerfuglen Steinerbarnehage AS | Education | 2004 |
| Sonar Studio Da | Information & communication | 2025 |
| Sondree Holding AS | | 2024 |
| Sone Invest AS | Professional & scientific | 2023 |
| Sonen AS | Real estate | 2018 |
| Sonic Flow AS | Professional & scientific | 2016 |
| Sonik AS | Information & communication | 2020 |
| Sonmik Holding AS | | 2023 |
| Sonofit AS | Manufacturing | 2024 |
| Sonstad AS | | 2006 |
| Sonstad Holding 2 AS | | 2019 |
| Sonstad Holding 3 AS | | 2019 |
| Sooe AS | Professional & scientific | 2015 |
| Sook Hodling AS | | 2025 |
| Soothing Relaxation AS | Information & communication | 2018 |
| Sorgenfri Buss AS | Transport & logistics | 2013 |
| Sorgenfriparken Utbygging AS | Real estate | 2015 |
| Sorgenfriveien 11 AS | Real estate | 2019 |
| Sorgenfriveien 12 Trondheim AS | Real estate | 2011 |
| Sorgenfriveien 14 AS | Real estate | 1964 |
| Sorgenfriveien 9 AS | Real estate | 2019 |
| Sorgente AS | Real estate | 2005 |
| Sosi Invest AS | Financial services | 2005 |
| Sosiologisk Poliklinikk AS | Education | 2014 |
| Sot/Sabrura Torget AS | Hospitality | 2019 |
| Sotbar AS | Hospitality | 2008 |
| Soto Entreprenør AS | Construction | 2016 |
| Soundscape Studios AS | Professional & scientific | 1996 |
| Source AS | Information & communication | 2017 |
| SPA24 AS | Wholesale & retail | 2023 |
| Spafor AS | Hospitality | 1987 |
| Spannavegen Eiendom AS | Real estate | 2010 |
| Spannlia Invest AS | Real estate | 2014 |
| Spapool Trondheim AS | Wholesale & retail | 2022 |
| Sparc Nordic AS | Information & communication | 2026 |
| Sparebank 1 Bilplan AS | Administrative & support | 1998 |
| Sparebank 1 Bygget Steinkjer AS | Real estate | 1983 |
| Sparebank 1 Finans Midt-Norge AS | Financial services | 1986 |
| Sparebank 1 Mobilitet Holding 2 AS | | 2023 |
| Sparebank 1 Næringsmegling AS | Real estate | 2025 |
| Sparebank 1 Private Equity I AS | Financial services | 2008 |
| Sparebank 1 Regnskapshuset SMN AS | Professional & scientific | 1985 |
| Sparebank 1 SMN | Financial services | 1823 |
| Sparebank 1 SMN Invest AS | Financial services | 2007 |
| SPAREBANK1 SMN Kvartalet AS | Real estate | 2006 |
| Spark Studio AS | Professional & scientific | 2012 |
| Spearo AS | Education | 2016 |
| Speed Syndicate Da | Wholesale & retail | 2008 |
| Speed Treningssenter AS | Arts & recreation | 2021 |
| Speider Eiendom AS | Real estate | 2021 |
| Speilet Eiendom AS | Real estate | 2021 |
| Speilet S 27 AS | Real estate | 2016 |
| Speleman AS | | 2024 |
| Spesial-Interiør AS | Manufacturing | 2017 |
| Spets AS | Wholesale & retail | 2019 |
| Spidergawd Management AS | Administrative & support | 2015 |
| Spillfabrikken AS | Wholesale & retail | 2020 |
| Spillum Prosjekt 1 AS | Real estate | 2023 |
| Spine AS | Information & communication | 1990 |
| Spire Interiør AS | Professional & scientific | 2018 |
| Spiren Fertilitetsklinikk AS | Health & social care | 2021 |
| Spirituell Dating AS | Other services | 2020 |
| Spirrevipp Holding AS | | 2025 |
| Spjot Holding AS | Real estate | 2016 |
| Sponhuset AS | Hospitality | 2000 |